Re: [PATCH v3 4/4] KVM: VMX: Allow direct access to MSR_IA32_SPEC_CTRL

[Jim Mattson]

On Tue, Jan 30, 2018 at 4:19 PM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> The new code in nested_vmx_merge_msr_bitmap should be conditional on
> vmx->save_spec_ctrl_on_exit.

But then if L1 doesn't use MSR_IA32_SPEC_CTRL itself and it uses the
VM-entry MSR load list to set up L2's MSR_IA32_SPEC_CTRL, you will
never set vmx->save_spec_ctrl_on_exit, and L2's accesses to the MSR
will always be intercepted by L0.